On Fri, Nov 4, 2022 at 8:12 AM Jun T <takimoto-j@kba.biglobe.ne.jp> wrote:
>
> 548         /* is this job in the foreground of an interactive shell? */
> 549         if (mypgrp != pgrp && inforeground &&
> 550             (jn->gleader == pgrp ||
> 551              (pgrp > 1 &&
> 552               (kill(-pgrp, 0) == -1 && errno == ESRCH)))) {
>
> But why just "jn->gleader == pgrp" is enough to assume that the foreground
> job has finished?
> [...]
> Another code that looks suspicious to me is (also in jobs.c)
>
> 478         if (pn->pid == jn->gleader)    /* if this process is process group leader */
> 479             status = pn->status;
> 480     }
>
> [...]
> If the line 478 is replaced by
>
> 478         if (WIFSIGNALED(pn->status) || pn->pid == jn->gleader)
>
> then [2] can be killed by a single ^C.

Thank you!  This is the clue I needed.

On line 476 is

476             signalled = WIFSIGNALED(pn->status);

If we change line 550 to be

550             ((jn->gleader == pgrp && signalled) ||

then all three examples start working.

Second patch attached, replaces the one from workers/50862.  Tests
pass, which is not surprising since all of this depends on signaling
interactive shells, but I have no idea how to write a regression test
for that.